Multihop Cellular Networks Research Articles

A Novel Approach for Improved Load Balancing and Interference Reduction in Wireless Networks using OFDMA

The quality of service offered to the user equipment in Multihop cellular networks with proper connection is affected severely due to the fading effects. These fading effects can lead to link loss between the user equipment (UE) and base station. This problem is severe when the UE traveling inside of tunnel, forests and big buildings. The duration of the link loss may vary from seconds to hours. Link loss management can control the link loss, increase the coverage area and signal quality in cell boundaries. It requires predictive power and link scheduling in cell sectors and signal quality enhancement at cell boundaries using filters. Interference Coordination and Load Balancing at base station and UE algorithm is used. This paper introduces a link loss management algorithm with load balancing to provide seamless service to users and this increases the Quality of Service (QoS) of safety critical communications.

Context-Aware Mode Selection for 5G Multi-Hop Cellular Networks

In the present day, 5G and beyond networks are being designed to support the future increase of data traffic and service demands. To support such increase, 5G networks will incorporate device-centric technologies with adequate mechanisms to scale and handle the growing and very large number of connected devices and traffic demands. Device-centric technologies include Device-to-Device (D2D) communications and Multi-hop Cellular Networks (MCNs). In device-centric wireless networks, devices will be able to connect to the network using two different connection modes: through a traditional cellular connection, or through a multi-hop cellular connection based on D2D communications with intermediate mobile devices. Device-centric technologies will therefore provide new connectivity options and significant opportunities to enhance the capacity and efficiency of 5G networks. However, new challenges will need to be addressed. One of them is the selection of the most adequate connection mode for each mobile device, because it will be key to improve the network performance and efficiency. This work proposes a context-aware mode selection scheme capable of identifying and selecting the most adequate connection mode for each device under a wide range of deployment and operating conditions. The proposed scheme estimates the benefits and risks of each connection mode based on context information available at the base station guaranteeing low signaling overhead. The obtained results show that the proposed mode selection scheme helps achieving throughput gains higher than 200% compared to traditional single-hop cellular communications for devices at the cell edge, and significant gains are also achieved compared to other mode selection schemes implemented and evaluated.

A Cellular Backhaul Virtualization Market Design for Green Small-Cell Networks

In this paper, we propose a green backhaul infrastructure virtualization market for a renewable-powered cellular multi-hop backhaul network in which a virtual operator (VO) can use the backhaul networks of some assemble operators (AOs) to forward traffic to itself. In particular, some backhaul nodes (i.e., on-grid nodes) of each assemble operator are considered to be powered by renewable energy suppliers (RPSs). In response to stochastic traffic demand, the virtual operator sets traffic service prices it will pay to the assemble operators, and the assemble operators set energy prices they will pay to the RPSs. In addition, each AO should determine the amount of renewable energy that will be reserved for the off-grid node, and each RPS should determine how much energy should be stored. This paper explicitly characterizes the equilibrium price and resource coordination strategies for such a mulit-stage resource virtualization market, so that the decentralized system can operates in a stable and efficient way. Based on that, we derive results regarding higher-level integrated backhaul structural choices by the virtual operator, such as whether it sets up the backhaul network independently or uses the integrated backhaul network and which operators to choose as assemble operators. A novel algorithm is developed to find the sequential equilibrium solution that can properly cope with these peer effects. The simulation results show that the proposed integrated green multi-hop backhaul system yields substantial gains for both operators and renewable energy suppliers compared with a non-virtualization backhaul network using conventional energy. The results also provide insights on how to manage cellular backhaul virtualization pricing and the cost of renewable energy for the design of green dense small cell networks in future mobile networks.

Mode Selection for 5G Heterogeneous and Opportunistic Networks

5G and beyond networks will offer multiple communication modes including device-to-device and multi-hop cellular (or UE-to-network relay) communications. Several studies have shown that these modes can significantly improve the Quality of Service (QoS), the spectrum and energy efficiency, and the network capacity. Recent studies have demonstrated that further gains can be achieved when integrating demand-driven opportunistic networking into Multi-Hop Cellular Networks (MCN). In opportunistic MCN connections, devices can exploit the delay tolerance of many mobile data services to search for the most efficient connections between nodes. The availability of multiple communication modes requires mode selection schemes capable to decide the optimum mode for each transmission. Mode selection schemes have been previously proposed to account for the introduction of D2D and MCN. However, existing mode selection schemes cannot integrate opportunistic MCN connections into the selection process. This paper advances the state of the art by proposing the first mode selection scheme capable to integrate opportunistic MCN communications within 5G and beyond networks. The conducted analysis demonstrates the potential of opportunistic MCN communications, and the capability of the proposed mode selection scheme to select the most adequate communication mode.

Energy efficient virtual network embedding for wireless multi-hop cellular networks using multi-commodity flow algorithm

With the rapid development of wireless mobile communication technologies, the trend of generalisation and centralisation requires variable communication devices and flexible network structures. To improve the transmission quality and extend the cell coverage, multi-hop relay network, as a wireless access network, has become an important part of communication system framework. Furthermore, to support seamless communication of multiple devices and services in heterogenous wireless networks with high resources utilisation, network virtualisation has been proposed to offer a flexible and scalable management. In this paper, we study the wireless multi-hop cellular network and the problem of virtual network embedding. We first analyse the wireless multi-hop cellular network scenario and establish a virtual network embedding model. After that we propose a minimum cost flow algorithm based on the multi-commodity flow algorithm. Thus the problem is transformed into a multi-commodity flow problem. We finally put forward an optimisation algorithm of Lagrange relaxation and sub-gradient algorithm to solve the problem. The simulation results show that the proposed multi-commodity flow algorithm can make full use of network resources, and improve the acceptance rate of virtual network requests, so as to improve the quality of service.

Energy efficient virtual network embedding for wireless multi-hop cellular networks using multi-commodity flow algorithm

With the rapid development of wireless mobile communication technologies, the trend of generalisation and centralisation requires variable communication devices and flexible network structures. To improve the transmission quality and extend the cell coverage, multi-hop relay network, as a wireless access network, has become an important part of communication system framework. Furthermore, to support seamless communication of multiple devices and services in heterogenous wireless networks with high resources utilisation, network virtualisation has been proposed to offer a flexible and scalable management. In this paper, we study the wireless multi-hop cellular network and the problem of virtual network embedding. We first analyse the wireless multi-hop cellular network scenario and establish a virtual network embedding model. After that we propose a minimum cost flow algorithm based on the multi-commodity flow algorithm. Thus the problem is transformed into a multi-commodity flow problem. We finally put forward an optimisation algorithm of Lagrange relaxation and sub-gradient algorithm to solve the problem. The simulation results show that the proposed multi-commodity flow algorithm can make full use of network resources, and improve the acceptance rate of virtual network requests, so as to improve the quality of service.

A Survey of Secure Routing Protocols in Multi-Hop Cellular Networks

Multi-hop networks are expected to be an important part of 5G mobile systems. In a multi-hop cellular network (MCN), the nodes assist each other in relaying packets towards their destinations. The structures and operations of multi-hop networks make them particularly vulnerable to certain types of attack. Hence, security measures to counter these attacks are necessary. In this paper, we provide an overview of the secure routing protocols for multi-hop networks and classify them into MCN Type-1 and Type-0 categories for device-to-device communications, and the Internet-of-Things category for machine-to-machine communications. Our focus is on the applied cryptographic techniques and the security mechanisms in secure routing protocols. We propose an evaluation framework incorporating different security aspects, vulnerabilities, and levels of deployability to compare a number of secure routing protocols. Moreover, we review the secure routing paths in software-defined networking as a solution for existing challenges in multi-hop networks. Some open research problems are highlighted as possible directions for future studies.

Routing in Multi-Hop Cellular Device-to-Device (D2D) Networks: A Survey

In recent years, device-to-device (D2D) communication has attained significant attention in the research community. The advantages of D2D communication can be fully realized in multi-hop communication scenario. The integration of cellular and multi-hop networks not only provides guaranteed quality of service and reliability as a traditional cellular network, but also has the flexibility and adaptability as a multi-hop network. Routing in such multi-hop cellular D2D networks is a critical issue, since the multi-hop network can perform worse than a traditional cellular network if wrong routing decisions are made. This is because routing in these multi-hop networks needs to take care of the node mobility, dynamic network topology, and network fragmentation, which did not exist in traditional cellular networking. This paper provides a comprehensive survey of routing in multi-hop D2D networks. Some future research directions for the routing in D2D networks are also discussed at the end of this paper.

Energy efficient topology control for multi-hop relay cellular networks based on flow management

The rapid expansion of mobile communication networks has led to a significant increase of energy consumption, and the energy consumption of wireless access networks accounted for nearly 90%. As an important form of the wireless access networks, multi-hop relay networks have been widely deployed in the existing cellular networks. Consequently, improving the energy efficient of multi-hop relay cellular networks is crucial for communication networks. In this paper, we design an energy flow management framework for multi-hop relay cellular networks, which contains routing planning, traffic adjustment and power allocation. In order to reduce the energy consumption and guarantee the system capacity, a heuristic algorithm is designed in this paper, which mixes the ant colony algorithm with convex optimization theory. In order to verify the effect of the proposed algorithm, we make numerical simulation and compare it with other network management strategies, such as ant colony algorithm, shortest path routing strategy and greedy algorithm. Simulation results show that by our algorithm, the energy consumption can be reduced compared with the ant colony algorithm, shortest path and greedy algorithm while ensuring the demand of quality of service (QoS).

On the Capacity Gain of Multi-Hop Cellular Networks With Opportunistic Networking and D2D: A Space-Time Graph-Based Evaluation

Previous studies have shown that device-centric wireless technologies, including multi-hop cellular networks (MCNs) and device-to-device communications (D2D), can increase the cellular network capacity. This letter progresses the current state of the art by deriving (using space-time graphs) the upper-bound capacity gains that can be further achieved when integrating efficiency-driven opportunistic networking into device-centric wireless networks. The increase is obtained without modifying the radio interface, and is not constrained to any particular radio interface.

Shortest and secure routing protocol for multi‐hop cellular networks (SSRP‐MCN)

AbstractNowadays, many advanced are developed and become available for users. So, the demand for a higher data rate wireless access significantly increases. For that reason, new cellular wireless networks have been introduced such as Worldwide Interoperability for Microwave Access (WiMAX), Long Term Evolution (LTE) and LTE‐advanced. However, the centralized topology of these technologies requires that the users have a direct connection to the Base Station (BS). Such topology suffers from congestion problem when a large number of users are communicating in the same time. To overcome the congestion problem, the Device‐to‐device and the mobile relays communications have been proposed to overcome the limitations of the conventional cellular architecture. These technologies can improve the cellular network capacity and reduce the infrastructure costs. However, security in multi‐hop cellular networks (MCNs) is a great challenge especially when other mobile nodes participate in the routing process. Existing works on this topic focus on ensuring security for routing information. However, most studies do not secure the data transmission after the route selection and do not simultaneously ensure all the security requirements. In this paper, we propose a new secure and reliable routing protocol for MCNs. The main objective of this protocol is to select only the trustworthy intermediate nodes to participate in the route construction. These trustworthy nodes perform the route discovery process in a secure way and so discover a secure path that does not contain any attacker as an intermediate node. The intermediate nodes of the selected route participate in establishing a group key. This key is used to secure the data transmission phase after route selection. To achieve anonymity, the BS assigns to each mobile that participates in the selected route a temporary identity. We evaluate our proposed protocol in terms of security using AVISPA tool, and we conduct some simulations using Network Simulator (NS‐2). The simulation results show that it is reliable and provides acceptable performance in terms of throughput, end‐to‐end delay and normalized routing load. Copyright © 2016 John Wiley & Sons, Ltd.

Resource Allocation Scheme for Multihop Cellular Networks Using Directional Transmission

Multihop cellular networks offer a cost-effective solution to the problem of achieving higher capacity and extending coverage by using relay stations (RSs) deployed within the coverage area of a base station (BS). We herein consider directional transmission based on adaptive beamforming in which multiple users are served at the same time using multiple directional beams; this represents one promising technology that could improve the capacity of multihop cellular network. In directional transmission, severe intra-BS/RS, inter-BS---RS, and inter-RS interferences can occur due to the concurrent transmission and accordingly, system performance can be degraded severely. In this paper, we propose resource allocation to maximize the system capacity of multihop cellular networks by taking into account these severe interferences caused in multihop cellular network using directional transmission. To alleviate the problem of high computational complexity, we propose a sub-optimal scheme. A heuristic scheme is also proposed which can be performed in distributed manner with lower computational complexity. Through simulation results, we show that the use of our proposed schemes increases system capacity.

Context-aware opportunistic networking in multi-hop cellular networks

5G networks will be required to efficiently support the growth in mobile data traffic. One approach to do so is by exploiting Device-to-Device (D2D) communications and Multi-Hop Cellular Networks (MCNs) in order to enhance the spectrum re-use and offload traffic over underlay networks. This study proposes to further improve the efficiency of transmitting mobile data traffic by integrating opportunistic networking principles into MCNs. Opportunistic networking can exploit the delay tolerance characteristic of relevant data traffic services in order to search for the most efficient transmission conditions in MCNs. The study first presents an analytical framework for two-hop opportunistic MCNs designed to identify their optimum configuration in terms of energy efficiency. Using this reference configuration, the paper then proposes a set of opportunistic forwarding policies that exploit context information provided by the cellular network. Numerical and simulation results demonstrate that opportunistic networking can significantly contribute towards achieving the capacity and energy efficiency gains sought for 5G networks. Under the evaluated conditions, the obtained results show that the proposed schemes can reduce the energy consumption compared to traditional cellular communications by up to 98% for delay tolerant services. In addition, the proposed schemes can increase the cellular capacity by up to 79% compared to traditional cellular communications.

Empirical models of the communications performance of Multi-hop Cellular Networks using D2D

Multi-hop Cellular Networks (MCNs) can improve the quality of service, capacity and energy-efficiency of traditional infrastructure-centric single-hop cellular systems. MCN systems can exploit Device-to-Device (D2D) communications and utilize the communications and computing capabilities of mobile devices. However, the communications challenges resulting from the use of mobile devices and D2D communications require empirical solid evidences of their performance benefits, and the design of robust communications and networking protocols. In this context, this paper presents a unique set of empirical models of the communications performance of MCN systems that utilize D2D communications. The models take into account the impact of the distance, propagation/visibility conditions, number of hops, and communication settings. The set of derived models can help design, test and optimize communications and networking protocols for MCNs that utilize D2D communications.

Multi-hop Cellular Networks for LoadBalancing and Interference CoordinationUsing OFDMA

Multi hop cellular networks (MCNs) use multiple low-power transmitters for high throughput and coverage of large area in a network. The network consists of Base stations (BSs) and Relay Stations (RSs) placed inside the center and edge of the network that could transmit the frequency simultaneously. The network performance can be affected by the mobile stations which lead to co channel interference (CCI) near the coverage boundary of the cell. The traffic quality and the quality of service (QOS) can hardly be guaranteed due to the unbalanced user distribution. The static method is used which divides the network into a tri-sector network according to the frequency reuse scheme that works with the downlink of OFDMA-based specification. The throughput increases by accommodating more users in the coverage area in a MCNs. Interference in the cell edge is avoided by implementing the avoidance algorithms where the base stations are placed in the centre of the cell and in tri-sector of the network.

Opportunistic Multihopping for Energy Efficiency: Opportunistic Multihop Cellular Networking for Energy-Efficient Provision of Mobile Delay-Tolerant Services

Cellular operators are facing considerable capacity and energy-efficiency challenges as cellular data traffic keeps rising. Several studies have shown that multihop cellular networks (MCNs) could help tackle these challenges through the integration of device-to-device (D2D) and cellular communications. This article demonstrates that significant energy- efficiency gains can be achieved when MCNs jointly exploit opportunistic networking and the traffic delay-tolerance characteristics of relevant mobile data services.

Contextual optimization of location-based routing protocols for multi-hop cellular networks using mobile relays

Traditional single-hop cellular architectures fail to provide high and homogeneous quality of service levels throughout a cell area due to the strong signal attenuation with the distance. In this context, multi-hop cellular networks that utilize mobile relays and device-to-device communications have been proposed to overcome the physical limitations of conventional cellular architectures. One of the key building blocks of multi-hop cellular networks is the multi-hop routing of information from the source to the destination. This paper investigates the performance and energy signaling benefits of location-based multi-hop routing protocols. In particular, the paper demonstrates the benefits of a contextual optimization of this type of protocols in order to achieve a high end-to-end performance, while reducing the energy and signaling implementation cost.

Power Control and Soft Topology Adaptations in Multihop Cellular Networks With Multi-Point Connectivity

The LTE standards account for the use of relays to enhance coverage near the cell edge. In a traditional topology, a mobile can either establish a direct link to the base station (BS) or a link to the relay, but not both. In this paper, we consider the benefit of multipoint connectivity in allowing User Equipment (UEs) to split their transmit power over simultaneous links to the BS and the relay, in effect transmitting two parallel flows. We model decisions by the UEs as to: (i) which point of access to attach to (either a relay or a relay and the BS or only the BS); and (ii) how to allocate transmit power over these links so as to maximize their total rate. We show that this flexibility in the selection of points of access leads to substantial network capacity increase against when nodes operate in a fixed network topology. Individual adaptations by UEs, in terms of both point of access and transmit power, are interdependent due to interference and to the possibility of over-loading of the backhaul links. We show that these decisions can converge without any explicit cooperation and derive a closed-form expression for the transmit power levels.

Marginal Power Efficiency Considerations in Power Control Adaptations for Multihop Cellular Networks

Marginal Power Efficiency Considerations in Power Control Adaptations for Multihop Cellular Networks

Multihop cellular: from research to systems, standards, and applications [Guest Editorial

It has been more than a decade since the multihop cellular network (MCN) architecture was first proposed and analyzed in 2000 [1]. As the transmission range decreases <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> times, the number of simultaneous transmissions and hop count increase by <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> times and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> times, respectively, which leads to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> times cellular capacity increase. Fundamental research projects have demonstrated the benefits of MCN in terms of system capacity, service coverage, and network connectivity. Many special issues have been devoted to this stream of research [2–6]. The actual concept behind the MCN architecture could be regarded as a hybrid of mobile ad hoc networks (MANETs) and cellular networks. This concept of "relaying within a cell" also pushed standard bodies to consider solutions embedded with mesh or ad hoc architectures, such as IEEE 802.11s [7], IEEE 802.15.5 [8], and IEEE 802.16j [9]. Now, in the recent standards of the Third Generation Partnership Project (3GPP), Proximity-Based Services (ProSe) [10, 11] related work items also cover the MCN concept. In addition to device-to-device (D2D) direct communications, user equipment (UE)–UE relay and UE–network relay are also supported features. Both infrastructural and infrastructureless architectures are considered. Among many use cases, the most urgent one is public safety. These show that MCN architecture realization is ongoing.